Road debris crashed through a vehicle's windshield, killing its elderly driver on northbound Highway 101 in Palo Alto, the California Highway Patrol said on Friday.

CHP officers said on Twitter that they believe a brass bolt kicked up by passing traffic struck the 82-year-old Mountain View man on the left side of his neck. The impact prompted him to swerve and collide with the center median, before eventually coming to a stop, according to the CHP's Redwood City Division.

According to AAA, road debris caused more than 200,000 crashes between 2011 and 2014, killing 500 people nationwide. This year, Caltrans has picked up more than 4,000 cubic yards of debris, ranging from litter to pieces of construction equipment, from San Mateo County roads.

It's not yet confirmed. It appears this may have been the projectile that may have been kicked by passing traffic. pic.twitter.com/lyjGadKvr0